1. Field
The present invention relates to an ion implantation apparatus configured to adjust the distribution of beam current in the longitudinal direction of a ribbon-like ion beam.
2. Background
Among the known types of ion implantation apparatuses are hybrid ion implantation apparatuses that introduce a ribbon-like ion beam into a processing chamber, move a substrate (a semiconductor substrate such as a silicon wafer) so that the substrate crosses the ion beam in a direction that intersects the short-side direction of the introduced ion beam, and thereby implants ions into the substrate.
This type of ion implanter is provided with a means that adjusts the uniformity of the ion beam current distribution in the long-side direction of the ribbon-like ion beam so that the amount of ion irradiation (dose) implanted into the substrate is uniform within the substrate surface.
A specific architecture, as disclosed in Patent Document 1, placed a plurality of pole pieces along the long-side direction of the ribbon-like ion beam in the magnetic pole part of a mass analyzing electromagnet and utilized a technique of adjusting the uniformity of the current distribution in the longitudinal direction of the ribbon-like ion beam by varying the magnetic field distribution in the longitudinal direction of the ribbon-like ion beam by adjusting the lengths of the pole pieces that protrude into the interior of the electromagnet.    [Patent Document 1] JP-A-H06-342639